This is an interesting perspective, and I assume your definition is the technically correct one. Still, many SEs receive substantial compensation in RSUs, direct stocks, shares in startups, et cetera. So also from this perspective, there are many non-working class SEs. Another aspect is that culturally, the perception has been that SEs don't necessarily sell their work by the hour, but instead sell knowledge that scales tremendously, in exchange for a comfortable upper middle-to-lower upper class life.